Melanin & Gray Hair
Melanin, produced by the follicle from which a hair grows, is responsible for that hair's black/brown or red/yellow base color. Other hair colors are produced when other agents produced by the body modify that base color. Gray and white hairs occur when hair follicles stop producing melanin. Does this Spark an idea?
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Melanin and hair color production
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According to Scientific American author Coco Ballantyne, melanin is produced by melanocytes, which send "packages" of melanin to the keratinocytes, which produce the hairs themselves. there are two different kinds of melanin that affect hair color. Eumelanin produces black or brown hair coloration, while pheomelanin produces red or yellow hair coloration.
The science behind melanin
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Eumelanin has a very precise rice-shaped appearance. It is formed through the interaction of the amino acid tyrosine and tyrosinase. By contrast, pheomelanin is created through the interaction of tyrosine and a second amino acid called cysteine. According to L'Oreal Hair-Science.com, cysteine is "rich in sulphur." Although the increased presence of one of these melanins is responsible for darker color being expressed, Scandinavian hair contains mostly eumelanin, contrary to what might be expected.
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Effects of aging on hair
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Aging may have different effects on different kinds of hair. The hair of a person who was born blond may darken as that person matures before turning gray later in life. Caucasians, blacks and Asians gray at different rate. According to author Michelle Buford, "by age 50, most people can expect 50 percent of their hair to be gray." In addition, men tend to start graying earlier than women.
Other causes of gray hair
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Some anecdotal evidence exists of stress causing gray hair. For example, the former presidents of the United States typically have full heads of gray hair at the end of their presidencies, whether or not they had extensive graying at the beginning of their terms. There is no scientific evidence of stress, smoking, free radicals or fright causing gray hair; however, interest remains in exploring those possibilities.
Spontaneous graying
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Certain natural effects can cause the illusion of spontaneous, rapid graying. According to Ballantyne, there is an autoimmune disease called "alopecia areata" that causes pigmented hairs to fall out while leaving gray or white ones behind. Alopecia areata may have its roots in stress.
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